Burner for blast stoves



Aug. 22, 1967 D. P. M KINNON ETAL BURNER FOR BLAST-STOVES Filed Feb. 12,1965 FIG: 1.

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DONALD .P. McK/NNO/V and STEVE OLEXEN Attorney United States Patent3,336,965 BURNER FOR BLAST STOVES Donald P. McKinnon and Steve Olexen,Lorain, Ohio,

assignors to United States Steel Corporation, a corporation of DelawareFiled Feb. 12, 1965, Ser. No. 432,109 2 Claims. (Cl. 158-109) Thisinvention relates to an apparatus for heating stoves. More particularly,the invention is directed to a burner particularly useful in conjunctionwith blast furnace stoves. Common blast furnace stoves comprise acombustion chamber to which is attached a gas burner which supplies gas(fuel) and air into the combustion chamber where the fuel is burned.Such stoves operate cyclically, alternating between combustion and airintake, the purpose of the stove being to heat incoming air by passingit through the stove after the stove has been heated.

Stoves of the type described above are generally heated by a burnerextending through a burner port into the stove. The burner supplies amixture of combustion gas and air which is ignited, sending a flame intothe stove. Typically, such burners extend through the port into thestove and are, therefore, subjected to extreme conditions of heat whichrequire them to be constructed of expensive materials capable ofwithstanding the high temperature to which they are exposed. In spite ofexpensive construction, however, burners which extend into the stovemust be frequently replaced.

The present invention provides a burner which can be positioned entirelyoutside of the stove but which still provides effective and eificientheating through the burner port to the interior of the stove. Theimproved burner, according to the invention, comprises tubularcombustion-air supply means which extends toward the burner port of thestove. Combustion gas is supplied through independent means into theinterior of the combustion-gas supply means by an arrangement which isessentially a tube within a tube terminating near the entrance of theburner port. An air and gas mixer which enables the burner to bepositioned outside the stove is fixed at the terminal end of thecombustiongas supply means in front of the burner port and within thecombustion-air supply means. The mixer comprises air-flow directingmeans symmetrically distributed about the perimeter of thecombustion-gas supply means and within the combustion-air supply means.The air-flow directing means directs a portion of supplied combustionair in a converging direction into the burner port. The mixer alsocomprises means at the mouth of the combustion-gas supply means fordirecting a portion of supplied combustion gas in a diverging flow intothe burner port. In this way, efiicient mixing of combustion air andcombustion gas is achieved within the burner port and when ignited,provides effective heating for the stove interior.

Further details and advantages of the invention will become apparentfrom the following description of the accompanying drawings whichillustrate a preferred embodiment of the invention. In the drawings:

FIGURE 1 is a fragmentary side elevation view of the of the burner andits adaptation with the burner port of a hot blast stove; and

FIGURE 2 is an enlarged partial side view of the burner taken alonglines IIII of FIGURE 1 showing the air and gas mixer of the burner.

As is seen in FIGURE 1, the side wall of a hot blast stove contains aburner port 12 used for supplying heat to the stove interior. A suitablevalve 8 is located at the burner port and is adapted to seal the burnerport when the stove is receiving cold air for preheating in the stovechamber. Any suitable valve such as the gate type shown in FIGURE 1 maybe used for this purpose. Positioned outside of the burner port but,advantageously, sealed thereto, is our improved burner 20. The burnercan be easily attached to the gate valve 8 or directly to the side wallof the stove by means of a flange 6 as shown.

The burner itself, 20, comprises combustion-air supply means 22 which isa tubular section extending toward the burner port and which receivescombustion air from a fan or blower ply of air. The burner may beconveniently supported on a stand made from steel plates and angles asshown.

Combustion gas is supplied through a tubular conduit 24 which deliversthe gas into the combustion-air supply means 22 through a tubularsection having a terminal portion 25 substantially parallel with thetubular combustionair supply means and having a common centerline witheach other and with the burnerport 12 of the hot blast stove 10. Themouth or terminal opening 26 of the combustion-gas supply meansterminates near the entrance of or in front of the burner port 12.Suitable means are provided to control the flow of combustion gas suchas the butterfly valve 23 shown in the drawing.

An air and gas mixer is fixedly positioned at the mouth 26 of thecombustion-gas supply means. The mixer comprises means 30 symmetricallydistributed about the outer perimeter of the mouth 26 (best shown inFIGURE 2) for directing a portion, but not all, of supplied combustionair in a converging direction into the burner port. The mixer itself ispreferably constructed as shown in FIGURES 1 and 2 with ribs 32 attachedto the mouth 26 of the combustion-gas supply means and to which tubularsections 30 are also attached. In the embodiment illustrated, foursymmetrically arranged tubular sections inclined toward the centerlineof the burner port 12 direct a portion but not all of suppliedcombustion air in a converging direction. Conical section 34 ispositioned at the center of the mouth 26 of combustion-gas supply meansso as to direct a portion, but not all, of the supplied combustion gasin a converging direction into the burner port 12. Ribs 32 are attachedat one end to the conical section 34 and to tubular sections 30 and attheir other end to mouth 26, as discussed above. As can be seen, aportion of combustion gas and combustion air are directed by the mixerinto intersecting paths producing a degree of turbulence which insureseffective mixing of the combustion air and combustion gas. The ribs 32may be secured to the tubular sections 30 and the conical section 34 bywelding and can also be welded to the mouth 26 of the combustion-gassupply means.

It is important that the air-flow directing means employed in the mixerbe symmetrically distributed about the combustion-gas supply means toinsure: uniform mixing. Although four sections of tubular configurationare shown in the drawings, other arrangements of differentconfigurations may be employed Which direct a portion of the combustiongas in a converging path symmetrically around the combustion-gas supplymeans.

It will be appreciated that the burner described herein avoids many ofthe safety hazards associated with conventional stove burners. Forexample, when not in operation, the burner is fully vented to theatmosphere through the fan and blower housing assembly. Moreover, onlyair is present in the outer cavity of the burner and there is littlepossibility of gas leakage into the surrounding atmosphere. The air andfuel mixer is positioned immediately adjacent the stove and thecombustion gas and air is mixed in the burner port thereby avoidingcombustion in the burner and permitting the burner itself to remain coolin operation. In this latter connection, it should be noted that the airand gas mixer is located ahead of the gas valve so that when the stoveis being heated, the flow 18 adapted to provide a controlled supof gascools the mixer and when the burner is turned 01f, the burner port gatevalve is closed and the mixer is not exposed to the radiant heat fromthe combustion chamber. Because the burner is not exposed to extremetemperature conditions, it may be constructed of low-cost carbon steelsand will last indefinitely. In the preferred embodiment, the burner isconstructed of round tubes providing a laminar gas flow which alsoresults in an economy of metal and reduction in welding as compared withother burners of rectangular design. The cylindrical surfaces of theburner eliminate pockets which would be otherwise difiicult to clean.

While one embodiment of our invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewtihout departing from the scope of the following claims.

We claim:

1. In a hot blast stove having a burner port through which a burnersupplies a flame of combustible gas, the improvement comprising a burnerpositioned entirely outside said port adjacent said stove and sealablyattached thereto, said burner comprising tubular combustion-air supplymeans extending toward said burner port, tubular combustion-gas supplymeans extending into said combustion-air supply means, saidcombustion-gas supply means having a mouth terminating in front of saidburner port, an

air and gas mixer fixedly mounted at the mouth of said combustion-gassupply means, air-flow directing means symmetrically distributed aboutthe outer perimeter of said mouth of said combustion-gas supply meansand within said combustion-air supply means for directing a portion ofsupplied combustion air in a converging direction into said burner port,means positioned at the mouth of said combustion-gas supply means fordirecting a portion of supplied combustion gas in a diverging flow intosaid burner port, whereby efficient mixing of combustion air andcombustion gas is achieved within the burner port.

2. The improvement according to claim 1 wherein the combustion-airsupply means and the terminal portion of the combustion-gas supply meansare substantially parallel tubular sections having a common centerlinewith each other and with the burner port of said hot blast stove.

References Cited UNITED STATES PATENTS 938,182 10/1909 Todd et al 1581091,962,113 6/1934 Elmore. 2,269,699 1/1942 Stoecker et al 1581093,195,872 7/1965 Schneider et al. 158109 X 3,217,781 11/1965 Curtis etal 158109 JAMES W. WESTHAVER, Primary Examiner.

